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1/*
2 * Read-Copy Update tracing for classic implementation
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
17 *
18 * Copyright IBM Corporation, 2008
19 *
20 * Papers: http://www.rdrop.com/users/paulmck/RCU
21 *
22 * For detailed explanation of Read-Copy Update mechanism see -
23 * Documentation/RCU
24 *
25 */
26#include <linux/types.h>
27#include <linux/kernel.h>
28#include <linux/init.h>
29#include <linux/spinlock.h>
30#include <linux/smp.h>
31#include <linux/rcupdate.h>
32#include <linux/interrupt.h>
33#include <linux/sched.h>
34#include <linux/atomic.h>
35#include <linux/bitops.h>
36#include <linux/module.h>
37#include <linux/completion.h>
38#include <linux/moduleparam.h>
39#include <linux/percpu.h>
40#include <linux/notifier.h>
41#include <linux/cpu.h>
42#include <linux/mutex.h>
43#include <linux/debugfs.h>
44#include <linux/seq_file.h>
45
46#define RCU_TREE_NONCORE
47#include "tree.h"
48
49static int r_open(struct inode *inode, struct file *file,
50 const struct seq_operations *op)
51{
52 int ret = seq_open(file, op);
53 if (!ret) {
54 struct seq_file *m = (struct seq_file *)file->private_data;
55 m->private = inode->i_private;
56 }
57 return ret;
58}
59
60static void *r_start(struct seq_file *m, loff_t *pos)
61{
62 struct rcu_state *rsp = (struct rcu_state *)m->private;
63 *pos = cpumask_next(*pos - 1, cpu_possible_mask);
64 if ((*pos) < nr_cpu_ids)
65 return per_cpu_ptr(rsp->rda, *pos);
66 return NULL;
67}
68
69static void *r_next(struct seq_file *m, void *v, loff_t *pos)
70{
71 (*pos)++;
72 return r_start(m, pos);
73}
74
75static void r_stop(struct seq_file *m, void *v)
76{
77}
78
79static int show_rcubarrier(struct seq_file *m, void *v)
80{
81 struct rcu_state *rsp = (struct rcu_state *)m->private;
82 seq_printf(m, "bcc: %d nbd: %lu\n",
83 atomic_read(&rsp->barrier_cpu_count),
84 rsp->n_barrier_done);
85 return 0;
86}
87
88static int rcubarrier_open(struct inode *inode, struct file *file)
89{
90 return single_open(file, show_rcubarrier, inode->i_private);
91}
92
93static const struct file_operations rcubarrier_fops = {
94 .owner = THIS_MODULE,
95 .open = rcubarrier_open,
96 .read = seq_read,
97 .llseek = no_llseek,
98 .release = single_release,
99};
100
101#ifdef CONFIG_RCU_BOOST
102
103static char convert_kthread_status(unsigned int kthread_status)
104{
105 if (kthread_status > RCU_KTHREAD_MAX)
106 return '?';
107 return "SRWOY"[kthread_status];
108}
109
110#endif /* #ifdef CONFIG_RCU_BOOST */
111
112static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
113{
114 long ql, qll;
115
116 if (!rdp->beenonline)
117 return;
118 seq_printf(m, "%3d%cc=%ld g=%ld pq=%d qp=%d",
119 rdp->cpu,
120 cpu_is_offline(rdp->cpu) ? '!' : ' ',
121 ulong2long(rdp->completed), ulong2long(rdp->gpnum),
122 rdp->passed_quiesce, rdp->qs_pending);
123 seq_printf(m, " dt=%d/%llx/%d df=%lu",
124 atomic_read(&rdp->dynticks->dynticks),
125 rdp->dynticks->dynticks_nesting,
126 rdp->dynticks->dynticks_nmi_nesting,
127 rdp->dynticks_fqs);
128 seq_printf(m, " of=%lu", rdp->offline_fqs);
129 rcu_nocb_q_lengths(rdp, &ql, &qll);
130 qll += rdp->qlen_lazy;
131 ql += rdp->qlen;
132 seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c",
133 qll, ql,
134 ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
135 rdp->nxttail[RCU_NEXT_TAIL]],
136 ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
137 rdp->nxttail[RCU_NEXT_READY_TAIL]],
138 ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
139 rdp->nxttail[RCU_WAIT_TAIL]],
140 ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
141#ifdef CONFIG_RCU_BOOST
142 seq_printf(m, " kt=%d/%c ktl=%x",
143 per_cpu(rcu_cpu_has_work, rdp->cpu),
144 convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
145 rdp->cpu)),
146 per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
147#endif /* #ifdef CONFIG_RCU_BOOST */
148 seq_printf(m, " b=%ld", rdp->blimit);
149 seq_printf(m, " ci=%lu nci=%lu co=%lu ca=%lu\n",
150 rdp->n_cbs_invoked, rdp->n_nocbs_invoked,
151 rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
152}
153
154static int show_rcudata(struct seq_file *m, void *v)
155{
156 print_one_rcu_data(m, (struct rcu_data *)v);
157 return 0;
158}
159
160static const struct seq_operations rcudate_op = {
161 .start = r_start,
162 .next = r_next,
163 .stop = r_stop,
164 .show = show_rcudata,
165};
166
167static int rcudata_open(struct inode *inode, struct file *file)
168{
169 return r_open(inode, file, &rcudate_op);
170}
171
172static const struct file_operations rcudata_fops = {
173 .owner = THIS_MODULE,
174 .open = rcudata_open,
175 .read = seq_read,
176 .llseek = no_llseek,
177 .release = seq_release,
178};
179
180static int show_rcuexp(struct seq_file *m, void *v)
181{
182 struct rcu_state *rsp = (struct rcu_state *)m->private;
183
184 seq_printf(m, "s=%lu d=%lu w=%lu tf=%lu wd1=%lu wd2=%lu n=%lu sc=%lu dt=%lu dl=%lu dx=%lu\n",
185 atomic_long_read(&rsp->expedited_start),
186 atomic_long_read(&rsp->expedited_done),
187 atomic_long_read(&rsp->expedited_wrap),
188 atomic_long_read(&rsp->expedited_tryfail),
189 atomic_long_read(&rsp->expedited_workdone1),
190 atomic_long_read(&rsp->expedited_workdone2),
191 atomic_long_read(&rsp->expedited_normal),
192 atomic_long_read(&rsp->expedited_stoppedcpus),
193 atomic_long_read(&rsp->expedited_done_tries),
194 atomic_long_read(&rsp->expedited_done_lost),
195 atomic_long_read(&rsp->expedited_done_exit));
196 return 0;
197}
198
199static int rcuexp_open(struct inode *inode, struct file *file)
200{
201 return single_open(file, show_rcuexp, inode->i_private);
202}
203
204static const struct file_operations rcuexp_fops = {
205 .owner = THIS_MODULE,
206 .open = rcuexp_open,
207 .read = seq_read,
208 .llseek = no_llseek,
209 .release = single_release,
210};
211
212#ifdef CONFIG_RCU_BOOST
213
214static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
215{
216 seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu ",
217 rnp->grplo, rnp->grphi,
218 "T."[list_empty(&rnp->blkd_tasks)],
219 "N."[!rnp->gp_tasks],
220 "E."[!rnp->exp_tasks],
221 "B."[!rnp->boost_tasks],
222 convert_kthread_status(rnp->boost_kthread_status),
223 rnp->n_tasks_boosted, rnp->n_exp_boosts,
224 rnp->n_normal_boosts);
225 seq_printf(m, "j=%04x bt=%04x\n",
226 (int)(jiffies & 0xffff),
227 (int)(rnp->boost_time & 0xffff));
228 seq_printf(m, " balk: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
229 rnp->n_balk_blkd_tasks,
230 rnp->n_balk_exp_gp_tasks,
231 rnp->n_balk_boost_tasks,
232 rnp->n_balk_notblocked,
233 rnp->n_balk_notyet,
234 rnp->n_balk_nos);
235}
236
237static int show_rcu_node_boost(struct seq_file *m, void *unused)
238{
239 struct rcu_node *rnp;
240
241 rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
242 print_one_rcu_node_boost(m, rnp);
243 return 0;
244}
245
246static int rcu_node_boost_open(struct inode *inode, struct file *file)
247{
248 return single_open(file, show_rcu_node_boost, NULL);
249}
250
251static const struct file_operations rcu_node_boost_fops = {
252 .owner = THIS_MODULE,
253 .open = rcu_node_boost_open,
254 .read = seq_read,
255 .llseek = no_llseek,
256 .release = single_release,
257};
258
259#endif /* #ifdef CONFIG_RCU_BOOST */
260
261static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
262{
263 unsigned long gpnum;
264 int level = 0;
265 struct rcu_node *rnp;
266
267 gpnum = rsp->gpnum;
268 seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x ",
269 ulong2long(rsp->completed), ulong2long(gpnum),
270 rsp->fqs_state,
271 (long)(rsp->jiffies_force_qs - jiffies),
272 (int)(jiffies & 0xffff));
273 seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n",
274 rsp->n_force_qs, rsp->n_force_qs_ngp,
275 rsp->n_force_qs - rsp->n_force_qs_ngp,
276 ACCESS_ONCE(rsp->n_force_qs_lh), rsp->qlen_lazy, rsp->qlen);
277 for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) {
278 if (rnp->level != level) {
279 seq_puts(m, "\n");
280 level = rnp->level;
281 }
282 seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d ",
283 rnp->qsmask, rnp->qsmaskinit,
284 ".G"[rnp->gp_tasks != NULL],
285 ".E"[rnp->exp_tasks != NULL],
286 ".T"[!list_empty(&rnp->blkd_tasks)],
287 rnp->grplo, rnp->grphi, rnp->grpnum);
288 }
289 seq_puts(m, "\n");
290}
291
292static int show_rcuhier(struct seq_file *m, void *v)
293{
294 struct rcu_state *rsp = (struct rcu_state *)m->private;
295 print_one_rcu_state(m, rsp);
296 return 0;
297}
298
299static int rcuhier_open(struct inode *inode, struct file *file)
300{
301 return single_open(file, show_rcuhier, inode->i_private);
302}
303
304static const struct file_operations rcuhier_fops = {
305 .owner = THIS_MODULE,
306 .open = rcuhier_open,
307 .read = seq_read,
308 .llseek = no_llseek,
309 .release = single_release,
310};
311
312static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
313{
314 unsigned long flags;
315 unsigned long completed;
316 unsigned long gpnum;
317 unsigned long gpage;
318 unsigned long gpmax;
319 struct rcu_node *rnp = &rsp->node[0];
320
321 raw_spin_lock_irqsave(&rnp->lock, flags);
322 completed = ACCESS_ONCE(rsp->completed);
323 gpnum = ACCESS_ONCE(rsp->gpnum);
324 if (completed == gpnum)
325 gpage = 0;
326 else
327 gpage = jiffies - rsp->gp_start;
328 gpmax = rsp->gp_max;
329 raw_spin_unlock_irqrestore(&rnp->lock, flags);
330 seq_printf(m, "completed=%ld gpnum=%ld age=%ld max=%ld\n",
331 ulong2long(completed), ulong2long(gpnum), gpage, gpmax);
332}
333
334static int show_rcugp(struct seq_file *m, void *v)
335{
336 struct rcu_state *rsp = (struct rcu_state *)m->private;
337 show_one_rcugp(m, rsp);
338 return 0;
339}
340
341static int rcugp_open(struct inode *inode, struct file *file)
342{
343 return single_open(file, show_rcugp, inode->i_private);
344}
345
346static const struct file_operations rcugp_fops = {
347 .owner = THIS_MODULE,
348 .open = rcugp_open,
349 .read = seq_read,
350 .llseek = no_llseek,
351 .release = single_release,
352};
353
354static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
355{
356 if (!rdp->beenonline)
357 return;
358 seq_printf(m, "%3d%cnp=%ld ",
359 rdp->cpu,
360 cpu_is_offline(rdp->cpu) ? '!' : ' ',
361 rdp->n_rcu_pending);
362 seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ",
363 rdp->n_rp_qs_pending,
364 rdp->n_rp_report_qs,
365 rdp->n_rp_cb_ready,
366 rdp->n_rp_cpu_needs_gp);
367 seq_printf(m, "gpc=%ld gps=%ld nn=%ld ndw%ld\n",
368 rdp->n_rp_gp_completed,
369 rdp->n_rp_gp_started,
370 rdp->n_rp_nocb_defer_wakeup,
371 rdp->n_rp_need_nothing);
372}
373
374static int show_rcu_pending(struct seq_file *m, void *v)
375{
376 print_one_rcu_pending(m, (struct rcu_data *)v);
377 return 0;
378}
379
380static const struct seq_operations rcu_pending_op = {
381 .start = r_start,
382 .next = r_next,
383 .stop = r_stop,
384 .show = show_rcu_pending,
385};
386
387static int rcu_pending_open(struct inode *inode, struct file *file)
388{
389 return r_open(inode, file, &rcu_pending_op);
390}
391
392static const struct file_operations rcu_pending_fops = {
393 .owner = THIS_MODULE,
394 .open = rcu_pending_open,
395 .read = seq_read,
396 .llseek = no_llseek,
397 .release = seq_release,
398};
399
400static int show_rcutorture(struct seq_file *m, void *unused)
401{
402 seq_printf(m, "rcutorture test sequence: %lu %s\n",
403 rcutorture_testseq >> 1,
404 (rcutorture_testseq & 0x1) ? "(test in progress)" : "");
405 seq_printf(m, "rcutorture update version number: %lu\n",
406 rcutorture_vernum);
407 return 0;
408}
409
410static int rcutorture_open(struct inode *inode, struct file *file)
411{
412 return single_open(file, show_rcutorture, NULL);
413}
414
415static const struct file_operations rcutorture_fops = {
416 .owner = THIS_MODULE,
417 .open = rcutorture_open,
418 .read = seq_read,
419 .llseek = seq_lseek,
420 .release = single_release,
421};
422
423static struct dentry *rcudir;
424
425static int __init rcutree_trace_init(void)
426{
427 struct rcu_state *rsp;
428 struct dentry *retval;
429 struct dentry *rspdir;
430
431 rcudir = debugfs_create_dir("rcu", NULL);
432 if (!rcudir)
433 goto free_out;
434
435 for_each_rcu_flavor(rsp) {
436 rspdir = debugfs_create_dir(rsp->name, rcudir);
437 if (!rspdir)
438 goto free_out;
439
440 retval = debugfs_create_file("rcudata", 0444,
441 rspdir, rsp, &rcudata_fops);
442 if (!retval)
443 goto free_out;
444
445 retval = debugfs_create_file("rcuexp", 0444,
446 rspdir, rsp, &rcuexp_fops);
447 if (!retval)
448 goto free_out;
449
450 retval = debugfs_create_file("rcu_pending", 0444,
451 rspdir, rsp, &rcu_pending_fops);
452 if (!retval)
453 goto free_out;
454
455 retval = debugfs_create_file("rcubarrier", 0444,
456 rspdir, rsp, &rcubarrier_fops);
457 if (!retval)
458 goto free_out;
459
460#ifdef CONFIG_RCU_BOOST
461 if (rsp == &rcu_preempt_state) {
462 retval = debugfs_create_file("rcuboost", 0444,
463 rspdir, NULL, &rcu_node_boost_fops);
464 if (!retval)
465 goto free_out;
466 }
467#endif
468
469 retval = debugfs_create_file("rcugp", 0444,
470 rspdir, rsp, &rcugp_fops);
471 if (!retval)
472 goto free_out;
473
474 retval = debugfs_create_file("rcuhier", 0444,
475 rspdir, rsp, &rcuhier_fops);
476 if (!retval)
477 goto free_out;
478 }
479
480 retval = debugfs_create_file("rcutorture", 0444, rcudir,
481 NULL, &rcutorture_fops);
482 if (!retval)
483 goto free_out;
484 return 0;
485free_out:
486 debugfs_remove_recursive(rcudir);
487 return 1;
488}
489
490static void __exit rcutree_trace_cleanup(void)
491{
492 debugfs_remove_recursive(rcudir);
493}
494
495
496module_init(rcutree_trace_init);
497module_exit(rcutree_trace_cleanup);
498
499MODULE_AUTHOR("Paul E. McKenney");
500MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
501MODULE_LICENSE("GPL");